But a new experiment has shown mums how to improve their well-being - by teaching themselves to be happy.

And by following the key steps, say experts, all mums should be able to lead a fulfilling and contented life.

The social experiment was launched by Netmums, an online support group set up in 2001 for mothers around the country.

Over 1,000 mums took part in the test, which asked them to follow 10 basic 'happiness principles'.

These included tasks which mothers could perform each day to try and boost their happiness levels, such as saying hello to a stranger, talking to a friend or doing someone else a good turn.

Mothers were also encouraged to do more exercise, watch less television and spend quality time with their partner.

Before the experiment, called 'Making Mums Happy', the participants took a psychological test, to rate their levels of happiness.

On a scale of 1 to 100, the average score was 52.

But after following the happiness principles for four weeks, the average score rose to 64 - a rise of over 10 per cent in just 28 days.

Netmums co-founder Sally Russell said yesterday: "Research has shown that mothers are at their least happiest stage in the first few years of bringing up their children because they are so stressed and overworked.

"Social isolation is one of the huge reasons for this, with people living further away from their families and receiving less practical and emotional support.

"Many more mothers now are also working, often juggling too much and finding themselves extremely busy."

Demands

The 40-year-old mother-of-two added: "The demands of looking after little ones can take its toll, and few mums and dads have little, if any, time to themselves.

"If the mother herself is not happy then it has an effect on the children, on the rest of the family and on the community as a whole.

"These steps are about mothers taking a little bit of time within their everyday life to do something more outward and something for themselves to make them feel more happy."

The 10 happiness principles were based on those used in the BBC TV programme Making Slough Happy, where experts worked with 50 volunteers from the Berkshire town to try and raise their happiness levels through experiments and community-based activities.

They involve simple steps such as keeping a diary of 'happy' events, cutting down on television viewing, befriending an elderly person and tending a plant.

Those who took part in that experiment registered a 33 per cent increase in their happiness levels at the end.

Happiness expert Richard Reeves, who worked on the show which was aired last year, said: "Happiness is a serious subject, and people are starting to see it as such.

"Some might say it's all obvious, that it's nothing we don't know. But what's different is that we can start to prove it, measure it.

"We can identify what the ingredients of happiness are."

Dr Jenny Bywaters, director of public health for the National Institute for Mental Health in England, said: "It is really important to spread the message about positive steps everyone can take to improve their sense of well-being and Netmums have shown how small changes can make a big difference."